Use a custom Matrix username

apps/registration/auth.py

@@ -0,0 +1,14 @@
+from cas_server.auth import DjangoAuthUser
+from django.utils.text import slugify
+
+
+class CustomAuthUser(DjangoAuthUser):
+    """
+    Override Django Auth User model to define a custom Matrix username.
+    """
+
+    def attributs(self):
+        d = super().attributs()
+        if self.user:
+            d["matrix_username"] = slugify(str(self.user.registration))
+        return d